That's a pretty important announcement for Switch. Not just because MK is traditionally a very popular game, but also because it's good that we have some of these big profile multiplat games immediately announced for Switch as well, which isn't the norm.
Another interesting thing is that a developer of the game said that the game is graphically and gameplay wise very similar to what we saw in the trailer, to the point that it will surprise us how similar it is.
And that's also interesting because it suggests it's a graphically challenging game, and it is still announced for Switch right away.
I'm worried about how it will look. I know a lot of people prefer any game over no game at all, and to an extent I do too (assuming the port is decent), but also for these big realistic looking triple A's the downgrades are a lot more noticeable than say for something like Valkyria Chronicles 4.
Smash for Switch actually looks surprisingly amazing so if it's 30fps on Switch it might have a chance of looking decent.
Also in terms of reveal trailers, the Mortal Kombat 10 trailer looks more visually impressive, but most likely just do to the way it was made. That dark shadow lighting next to the white snow is so beautiful.